The tension here comes entirely from resource math and hard choices rather than monsters or plot twists, and it works really well. The Manoeuvre Reserve system elegantly forces trade-offs between rescuing Survey Three, reaching shelter, and time itself. I especially liked that none of the NPCs are obstacles for their own sake: Marr, Li, and Mission Control all have legitimate, sympathetic reasons to say no. The solo-play NPC reaction table is a smart, lightweight solution too.
My only note is the prose is quite dense in places. Bullet points or just a summary table of costs/options might help. Also, white space is a must-add if you go for a V2.
Great grounded, hard-sci-fi tension overall. Terrific job!